Don't listen to skillionaire and gideon Steve, they're talking a pantload. No one gives you a formula sheet and there are no iPods allowed. And anyone who's actually taken a test knows they don't grade it for you on the way out. I don't think those guys are actual candidates, they're just on this bboard trying to foment confusion.
The fundamental premise of the CFA charter granting process is fairness -- everybody plays by the same rules. The exam day procedures reflect this fully. Knowing that people differ in their abilities to condense book material, the cfai doesn't allow notes or aptly named "cheat sheets". However it's fair for people to bring in their original texts, _without_ underlining or other value-added devices, to reference in a quiet fashion that doesn't disrupt other test takers. You can also bring a copy of the Code of Ethics, but again only if it's free from underlining.